Gasoline composition



United States Patent GASOLINE coMPosiTloN Harrison W. Sigworth, El Cerrito, and Eddie G. Lindstrom and Maurice R. Barusch, Richmond, Califi, assignors to California Research Corporation, San Francisco, Calif., a corporation of Delaware No Drawing. Application April 8, 1954 Serial No. 421,964

5 Claims. (Cl. 44-63) eration. This problem of poor idling operation has been accentuated and expanded with the increased traffic density in metropolitan areas and the use of multi-throat carburetors in private automobiles. It has been determined that a primary factor in poor idling operation is an accumulation of deposits in the throttle body section of the carburetor which causes an over-rich mixture at idle and a reduction in idle speed. The accumulation of deposits in the induction system of the engine and particularly in the throttle section of the carburetor is particularly pronounced in services requiring considerable idling, such as taxicab and door-to-door delivery service. In private automobile operation, this problem is particularly emphasized in the metropolitan areas where heavy city trafiic is encountered With appreciable stop-and-go driving.

The critical accumulation point for these deposits is adjacent to the throttle plate, whose position controls the air-fuel ratio. As these deposits accumulate, the air flow at idle'is restricted with no change in fuel flow, and a rich mixture results causing erratic idling and engine stalling. In order to compensate for the presence of these deposits, the throttle must be opened slightly by increasing the idle speed adjustment which, although allowing more air flow, automatically supplies more fuel. This requires a fuel correction by changing the idle mixture adjustment screw 21 compensating amount. justment required to maintain satisfactory idle performance is an indication of the rate of deposit build-up. Furthermore, deposits will often form in the idle air passageway causing restriction Which allows manifold vacuum to draw more gasoline into the engine, again causing rich idle and engine stalling.

it has been established that the primary source of these deposits is the contaminants in the intake air of the engine when operating at idle. The greatest source of these intake air contaminants is engine blow-by, which accounts for approximately one-half of the deposits. Exhaust from other vehicles, dust, and other components classed as normal air pollutants contribute to the formation of deposits.

The hydrocarbon components of the gasoline fuel bear no direct relation to the formation of these deposits. Tests have indicated that unstable or aged gasolines having a high ASTM gum or high potential gum values produce no greater deposits than stable, low-gum gasolines under comparable operating conditions.

The amount of idle ad 'ice Eli

In contrast to the periodic mechanical adjustments and engine reconditioningnecessary to compensate for the presence of the carburetor and induction system deposits, it has now been found possible to provide a fuel composition which is capable of preventing an accumulation or build-up of these deposits and Will also function to reduce the existing deposits. Thus, by operating a sparkignition engine with a fuel composition compounded in accordance with the present invention, it is possible to materially improve the idling operation of the engine and sustain this improved operation even under adverse conditions of intake air pollution.

it has been discovered that the incorporation, in a hydrocarbon base fuel boiling within the gasoline boiling range, of a small amount of a 1,2 substituted imidazoline bicarbonate, in Which the l-substituent is an aliphatic radical containing not more than 6 carbon atoms and the Z-substituent is an acyclic hydrocarbon radical containing 11 to 17 carbon atoms, will provide a gasoline composition which will effectively inhibit a carburetor deposit build-up in an engine operated thereon. In addition, a gasoline composition containing this improving agent will also substantially reduce and prevent the formation of deposits throughout the of the air-fuel induction system of the engine. These unique improving agents comprise the bicarbonate salts of a substituted imidazoline which may be represented by the following general formula:

in which R is an acyclic hydrocarbon radical containing 11 to 17 carbon atoms, and R is an aliphatic radical containing not more than 6 carbon atoms or, preferably, at least 2 and not more than 6 carbon atoms.

While the choice of specific compounds within the foregoing class of improving agents is dependent upon the number of factors, the compounds possessing the optimum improving characteristics are the bicarbonate salts of the imidazolines possessing a terminal -OH or -NH in the definition of R in the above formula. Representative of these preferred types of imidazolines are I-(Z-hydroxyethyl)-2-heptadecenyl-Z-imidazoline and 1 (2 aminoethyl) -2-heptadecenyI-Z-imidazoline.

The particular imidazolines whose bicarbonate salts form the preferred compounds of the invention may be derived by reacting a higher fatty acid, such as lauric, myristic, palmitic, linoleic, stearic and oleic acid, with a polyalkylene polyamine or the N-(ethylene oxide) derivatives of ethylene diamine under such conditions as to remove 2 moles of Water of hydration. The bicarbonate salts of these substituted imidazolines may be prepared in a conventional manner, as by saturating a solution of imidazoline and a molar excess of water with carbon dioxide at atmospheric temperature. It is usually preferred to prepare the bicarbonate salts in the form of a concentrate solution to facilitate handling problems and permit a simple blending operation in the incorporation of the additive in the gasoline. When preparing the concern trates, it is desirable to incorporate the substituted imidazoline in a desired hydrocarbon solvent Whose viscosity and boiling range are at least no greater than that of the gasoline to be compounded. The solution of the imidazoline in the hydrocarbon solvent, and particularly an aromatic solvent, containing the molar excess of water, is then saturated with carbon dioxide. For viscosity reasons, the concentration of the imidazoline bicarbonate in the hydrocarbon solvent will usually range from about 10% up to the limit of solubility, a range which normally lies between 10 and 70 percent by weight.

The improving agents of the invention, by reason of their unique elfectiveness, are incorporated in the hydrocarbon base fuel in relatively small amounts and, preferably, within the range of about 0.0003 to 0.1 percent by weight. Although larger concentrations may be employed, their effectiveness insofar as the reduction of carburetor deposit build-up does not materially improve with additional concentration of the additive.

In addition to the subject improving agent in the fuel composition, other conventional fuel additives may be incorporated. Of particular importance is the incorporation of a small amount, for example, between 0.05 to 0.5 percent by volume, of a nonvolatile oil, such as a light mineral lubricating oil, which has been found effective in combination with the subject improving additive to reduce deposits in the area of the intake ports of the engine.

The following examples are presented to illustrate the preparation and unique characteristics of representative improving agents of the invention.

60 parts by weight of l-(hydroxyethyl)-2-heptadecenyl- Z-imidazoline (neut. eq., 360), 40 parts by weight of toluene and 9 parts by weight of water (3 theories) were mixed to form a solution which was then saturated with carbon dioxide at room temperature. The salt formation liberated heat, raising the temperature to about 57 C. The product obtained was a viscous liquid. The concentration of the toluene solvent was adjusted of 40 percent by the addition of toluene as required. The finished product was a clear, somewhat viscous liquid having the following analysis:

Found Calculated Equivalent Weight- 650 702 Per Cent 4. 98, 4. 86 6. 3 Specific Gravity .94 a SS 537. 9 ASTM D 664 Titration:

Initial pH 10. 6 Total Base No., mg KOH per g 90. 80

, The product was further characterized as a bicarbonate salt by a potentiometric titration curve obtained with a Beckmann glass electrode pH meter. When a 0.5 gram sample in a solvent composed of 40 ml. of ethyl ether, 40 ml. of ethanol, and ml. of water was titrated with 0.1 N aqueous hydrochloric acid, the titration curve had a single plateau with a mid pH of about 8.3. Back titration with base after the addition of barium chloride or blowing with nitrogen to remove the interference of CO gave a titration curve typical of the imidazolinium chloride with a mid pH of 10.4.

Example II A laboratory test was developed to correlate the formation of carburetor deposits with field experience. In this test, a glass throttle body is inserted between the float section and the cast iron throttle body of a conventional carburetor. This glass throttle body is a section of glass tubing A-inch thick, approximately 1% inches inside diameter, and about 2 inches long. About %-inch down from the upper edge, holes are drilled diametrically to receive a conventional metal throttle plate and shaft. The carburetor and engine employed in the test are those of a 1952 Plymouth.

The engine is started with the throttle plate in the cast iron body controlling the speed, and the throttle plate in the glass body wide open. When the engine is warmed up so that no danger of backfiring exists, the throttle in the glass body is made to assume the throttling function, and the plate in the iron body is opened wide. Two small tubes carry the idle mixture from the float section to appropriate passageways in the cast iron throttle body.

The engine is operated a total of two hours on the test gasoline at about 500 R. P. M. idle, with five full-throttle, no-load accelerations, up to a speed of about 3000 R. P. M. every 15 minutes during the test period. During each run, all of the engine blow-by is piped to the engines air cleaner atop the carburetor. At the end of the test run, the engine is shut down and the glass throttle body removed and rated in accordance with the degree of deposits on a scale ranging from 1 to 7. A rating of 1 indicates a complete lack of deposits with the throttle body clean, and a rating of 7" indicates substantially complete coverage with black, opaque deposits. This test procedure and the rating of compounded gasolines obtained thereby have found excellent correlation with actual test operations in the field.

In accordance with the foregoing test procedure, the following representative data were obtained:

Fuel Deposit Rating 1 Base fnnl Base fuel+30 p. p. m. 1-(hydroxyethyl)-2-heptadecenyl-2- imidazoline.

Base fuel+30 p. p. m. 1-(hydroxyethyl)-2-heptadecenyl-2 imidazoline bicarbonate A '2' s t ews s sw g {O euwouamcaocq 1 All deposit ratings corrected to a base fuel rating of 6.0.

The base fuel employed was a commercial leaded regular gasoline which is representative of nationally-available commercial gasolines. As was previously mentioned, the hydrocarbon composition of the base fuel has a negligible effect upon the formation of carburetor deposits except as it influences the composition of the blow-by and the test results given above on the base fuel will be approximately the same, irrespective of the stability, gum content, or other characteristics of the hydrocarbon components of the fuel. The unique characteristics of the bicarbonate salt of the imidazolines of the invention do not extend to other organic or inorganic salts of these compounds.

In support of the unique characteristics of the bicarbonate salt, the following comparative test data are presented. In these tests, a standard leaded gasoline is incorporated with 60 p. p. rn. of the bicarbonate, acetate, chloride, and formate salts of 1-(hydroxyethyl)-2-heptadecenyl imidazoline. The results obtained are as follows:

Deposit rating Bicarbonate 3.3, 3.5 Acetate r 5.4 Chloride 6.0 Formate 5.2

In addition to the foregoing test data, a gasoline composition compounded in accordance with the present invention was field tested in representative fleet service and private automobile operation over an extended period of time with periodic inspection of the air-fuel induction systems of the engines and in particular the carburetors. In all instances, the test fuel not only inhibited the formation of carburetor deposits, but also was effective in removing existing deposits within the carburetor and the intake manifold, and permitted continuous satisfactory operation extending beyond periods where, normally, carburetor overhauling was to be expected.

Obviously, many modifications and variations of the invention, as hereinbefore set forth, may be made Without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A gasoline composition capable of reducing deposits normally formed in the induction system of a spark-ignition engine which comprises a major portion of a hydrocarbon base fuel boiling within the gasoline boiling range having incorporated therein a small amount, sutficient to reduce said deposits, of a 1,2 substituted imidazoline bicarbonate in which the l-substituent is a radical selected from the group consisting of hydroxyethyl and aminoethyl radicals and the 2-substituent is an acyclic hydrocarbon radical containing 11 to 17 carbon atoms.

2. An improved gasoline composition which comprises a major portion of a hydrocarbon base fuel boiling within the gasoline boiling range having incorporated therein about 0.0003 to 0.1 percent by weight of a 1,2 disubstituted imidazoline bicarbonate in which the l-substituent is a radical selected from the group consisting of hydroxyethyl and aminoethyl radicals and the 2-substituent is an acyclic hydrocarbon radical containing 11 to 17 carbon atoms.

3. An additive concentrate capable of incorporation into a gasoline which comprises a hydrocarbon solvent 6 having dissolved therein an amount ranging from about 10 percent up to the limit of solubility of a 1,2 substituted imidazoline bicarbonate in which the l-substituent is a radical selected from the group consisting of hydroxyethyl and aminoethyl radicals and the 2-substituent is an acyclic hydrocarbon radical containing 11 to 17 carbon atoms.

4. A gasoline composition capable of reducing deposits normally formed in the induction system of a spark-ignition engine which comprises a major portion of a hydrocarbon base fuel boiling within the gasoline boiling range having incorporated therein a small amount, sufficient to reduce said deposits, of l-(hydroxyethyl)-2-heptadecenyl2- imidazoline bicarbonate.

5. A gasoline composition capable of reducing deposits normally formed in the induction system of a spark-ignition engine which comprises a major portion of a hydrocarbon base fuel boiling within the gasoline boiling range having incorporated therein a small amount, sufiicient to reduce said deposits, of 1-(aminoethyl)-2-heptadecenyl 2- imidazoline bicarbonate.

References Cited in the file of this patent UNITED STATES PATENTS 2,550,982 Eberz May 1, 1951 2,553,183 Caron et a1 May 15, 1951 2,622,018 White et al Dec. 16, 1952 2,668,100 Luvisi Feb. 2, 1954 2,773,879 Sterlin Dec. 11, 1956 

1. A GASOLINE COMPOSITION CAPABLE OF REDUCING DEPOSITS NORMALLY FORMED IN THE INDUCTION SYSTEM OF A APARK-INGITION ENGINE WHICH COMPRISES A MAJOR PORTION OF A HYDROCARBON BASE FUEL BOILING WITHIN THE GASOLINE BOILING RANGE HAVING INCORPORATED THEREIN A SMALL AMOUNT, SUFFICIENT TO REDUCE SAID DEPOSITS, OF A 1,2 SUBSTITUTED IMIDAZOLINE BICARBONATE IN WHICH THE 1-SUBSTITUENT IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF HYDROXYETHYL AND AMINOETHYL RADICAL AND THE 2-SUBSTITUENT IS AN ACYCLIC HYDROCARBON RADICAL CONTAINING 11 TO 17 CARBON ATOMS. 